Resumen

HERNANDEZ, Francisco Javier et al. Ratio volume equations of Pinus oocarpa Schiede ex Schltdl. from Nayarit State, Mexico. Rev. mex. de cienc. forestales [online]. 2023, vol.14, n.78, pp.117-140.  Epub 14-Sep-2023. ISSN 2007-1132.  https://doi.org/10.29298/rmcf.v14i78.1330.

Ratio volume equations are precise mathematical alternatives to estimate merchantable volume of tree species. The objective of the present study was to evaluate the goodness of fit of three commercial volume models associated to height ratio and three taper models to conform a commercial volume-taper equations system of Pinus oocarpa growing at the state of Nayarit, Mexico. To carry out this study, 76 trees were selected for models fitting and 20 for validation over the entire study area. The models were fitted applying seemingly unrelated regression (SUR) in the statistic software SAR 9.2. The goodness of fit of the models was evaluated throughout the comparison of the Coefficient of determination, Root mean square error, Coefficient of variation and Akaike Information Criterium; meanwhile, it was considering the mean bias, absolute mean error, aggregate difference in percentage, Coefficient of determination, Root mean square error and the value of the slope parameter of a lineal regression model for equations validation. The Coefficient of determination and Root mean square error of the best commercial volume model were 0.9727 and 0.0651, and for taper models were 0.9579 and 2.7797, respectively. The validation process allowed to select the commercial volume and taper equations system S2 as the best to estimate volume and diameter at any stem height of P. oocarpa.

Palabras llave : Tree taper; Pinus oocarpa Schiede ex Schltdl.; Schumacher-Hall; commercial volume; ratio volume; total volume.

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